The present invention relates in general to insulation compositions and in particular to insulation compositions suitable for utilization in sealing breaches in architectural barriers.
It is known to seal breaches in architectural barriers with insulation materials to prevent the spreading of fire or flooding conditions throughout a structure. Typically, fiberglass, rock wool or other well known insulating materials are utilized for these purposes; however, these materials are not suitable for insulation in radioactive areas since they lack sufficient radiation attenuation characteristics to effectively block radiation leakage from a structure.
The necessity of providing an insulation material which will attenuate radiation has led to the development of flexible gel-like materials which may be altered to enhance their density and thus their radiation attenuation characteristics. To this end, it is known to provide a jelly-like substance, such as silicone gel, and to suspend powdered lead within the gel to greatly increase the density thereof. Silica sand or other materials are typically utilized to maintain the lead in suspension until such time as the gel has sufficiently cured. The altered gel is then utilized to insulate breaches in architectural barriers through which piping, wiring and other objects may pass.
The known composition comprised of silicone gel and powdered lead is reasonably suitable for most applications; however, in those situations in which a metal pipe passes through the architectural breach, it is necessary to maintain the gel in a flexible state to accommodate the expansion and contraction of the pipe in response to variations in temperature conditions. Known silicone gel/lead compositions demonstrate a tendency to cure excessively when exposed to gamma radiation, due to cross linking of the polymers present in the silicone gel. This excessive hardness will prevent the gel composition from accommodating the expansion or contraction of pipes and may result in a condition which will permit fire, flooding or gamma radiation to leak through the structure.